Pink line on edge of 1280x800 HDMI display

Technical Support
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1

Hello,

I am using the ixora carrier board v1.2 and apalis imx8 som with a 1280x800 hdmi display. I am utilizing TC 6.4 build 5.

I have seen a consistent pink line down the edge of the left side of the screen. I have changed hdmi cables and they all still show the line. I have tried a few different hdmi screens and they all show the pink line on the display. Would appreciate any help.

Thanks, Mike

2

Greetings @MikeHA,

Strange, on first impression I would assume some kind of display/setup specific issue. That is to say I haven’t seen a “pink line” or other kinds of display distortion on the HDMI screens I use. Typically such issues would denote something wrong with the display information, EDID in this case, or some hardware/connection related issue.

I have tried a few different hdmi screens and they all show the pink line on the display.

Are all these different displays from the same brand/model or completely different?

It’s hard for me to say really what the issue could be here. But my impression for now at least is that I don’t think it’s software related. Otherwise this issue would be more widespread and seen by us and others.

Best Regards,
Jeremias

3

Hello @MikeHA and @jeremias.tx

My company had exactly the same issue with a Verdin i.MX8MPlus module. It happened in the Evaluation board with connected HDMI Monitor as well as in our self developed customer baseboard with an USB-C Monitor connected. What we saw was that with deactivation of Plymouth the pink line artefact was gone. We use the Torizoncore 5.7.2 BSP.

BR Stefan

4

@swr thanks for chiming in!

Is disabling plymouth as simple as removing the splash screen customization from the tcbuild.yaml file or may I ask how you went about doing that? I have had a splash screen included within my tcbuild file.

@jeremias.tx is there any documentation out there on disabling plymouth? I searched around and didn’t see anything here: Splash Screen on Torizon OS | Toradex Developer Center

Thanks for the help!

5

Huh, this is the first time I’ve ever heard of Plymouth creating graphical distortions like this on our systems.

is there any documentation out there on disabling plymouth?

I believe you can just add something to the Kernel command line like as seen here: Plymouth - ArchWiki

Though I never tried this on our systems before so I’m not sure if there will be any impact. I’m curious what method @swr used to disable Plymouth.

Best Regards,
Jeremias

6

@MikeHA disabling plymouth seems not to be so easy. I found somewhere in the web a let’s say “dirty hack”. I just removed the themes folder so that plymouth is not able to find any theme. Initially we did this because we were searching for possibilities to speed up the boot process a little bit and find out by coincidence that this pink line has gone

7

@MikeHA, if you try this method could you let us know the results? I’m very curious about the connection here between Plymouth and this “pink line” if they are related or not.

Best Regards,
Jeremias

8

I attempted the solution you recommended @jeremias.tx and that was unsuccessful.

I attempted to remove the themes folder that @swr recommended but was getting an error that the folder was read only and couldn’t be removed even as root. I tried to change the permissions but was not successful. I’m unsure if there is another way to remove a read-only directory like that?

Thanks Mike

9

Honestly I’m still kind of skeptical whether the splash screen has anything to do with this pink line. Especially since you’re using the imx8 HDMI output, which doesn’t even output the splash screen if I recall: Splash Screen on Torizon OS | Toradex Developer Center

I recall in another thread of yours you were powering the module and display off the same power supply. This casued some race condition type issues for you due to the timing of things getting powered-on: 1280x800 hdmi screen not displaying via hdmi

As a sanity check have you tried separately powering the module and display? When doing this maybe also try using the display’s built-in edid instead of the one you’re providing externally. Just want to make sure it’s not some kind of race or edid issue again.

Best Regards,
Jeremias

10

Hey Jeremias,

this does show up when the screen is powered separately as well as with the base edid. We have seen this on multiple screens as well with varying edids but have also tested screens that did not have this but did not work for other reasons.

11

Well I don’t have a lot of ideas then. Most research says that a pink line on HDMI is indicative of some kind of hardware/connection issue. I have multiple HDMI displays, but they all work fine with no pink line or other graphical distortions.

Have you tried flashing other graphical images other than Torizon? For example our Qt or Multimedia image. I’m curious if you see the pink line as well on these other OS images or if this is somehow Torizon specific.

Best Regards,
Jeremias